A shift-by-wire type gearshift device includes an operation member that is mechanically separated from a transmission. Such type of a gearshift device includes a position sensor that detects an operation position of an operation member. The gearshift device electrically processes the detection signal of the position sensor to shift transmission modes.
Japanese Laid-Open Patent Publication No. 2008-309303 describes a position sensor that includes a magnet and detection elements. The publication describes a failsafe technique that allows for detection of the position of a shift lever even when one of the detection elements fails to function. The publication also describes the use of a timer to distinguish failure of a detection element from normal transition conditions of each detection element.
However, a failsafe may result in a complicated magnetization process. This increases the cost and size of of the magnet.